Sand wheel



Nov. 29,- 1949 E. A. FOSTER 2,489,630

SAND WHEEL Filed Sept. 11, 1946 4 Shets-Sheet 1 NOV. 29, 1949 FOSTER 2,489,630

SAND WHEEL Filed Sept. 11, 1946 4 Sheets-Sheet 2 FIE I3 E. A. FOSTER Nov. 29, 1949 SAND WHEEL 4 Sheets-Sheet 4 Filed Sept. 11, 1946 Fl-E E Patented Nov. 29, 1949 UNITED STATES PATENT ()FFICE -2 g4s9,630 SAND wnnEL Edward A; Fosten'Hayward, @alif assignor to Ynba Manufacturing company, .San Francisco,

Calif., a" corporation of California Application September 11, 1946, Serial No. new

4 claims." (01. 210- 149) My invention relates to means for separating materials of difierent natures and is particularly concerned with the separation of sand or silt from water particularly in connection with a min ing operation of the alluvial dredging type. f

In certain dredging operations the material handled by and released from the value-saving equipment includes with the water a relatively large proportion of fine s'and coarse sand, silt and comparable inert solids. If this inert mate: rial is discharged overboard back into the dredge pond along with the water, it tends to settle near the intake and is picked up again by the dredge along with the pond water and is recycled through the value recovering mechanism without any pos sibility of recovery of values therefrom. It is dis advantageous in general to discharge such inert fiiaterial into the dredge pond and it is desirable to remove it from the cycle once it has been proc essed through the value-saving equipment.

It is therefore an object of my invention to provide means for separating the relatively fine iriert material from the bulk of the material handld in a dredging operation, and returning only that material which is advantageous to the dre'dg-' ing pond.

Another object of the invention is to provide a means for separating from the material being processed sand and like material and dischargmg it at a remote point. I

An additional object of the invention is to remove from circulation inert, relatively fine material taking no productive part in the dredging operation.

an additional object of the invention is to provide means for relieving a cyclic processing mechanis'in of material not of value in the process.

A further object of the invention is to provide means readily accommodated on present dredges fdiseparating unwanted materials from those handled.

An additional object of the invention is in general to improve dredges and material handling equipment.

The foregoing and other objects of the invention are attained in the embodiment of the invention chosen for illustration in the accompanying drawings in which Figure 1 is a plan of a portion of a dredge including a sand wheel in accordance with the invention.

Figure 2 is an end v i'ew, parts being in cross section, of a dredge on which is installed asand wheel in accordance with the invention.-

Figure 3 is aside elevationofasan'd wheel Y 2 according to the invention, portions of the onclosing structure being broken away to disclose the interior mechanism some of which is illustrated in cross section.

I Figure 4 is across section to an enlarged scale, the plane of section being indicated by the toe ii -j of Figure 3.

Figure 5 is an isometric perspective of a fraghientary portion of the sand wheel of my inventron, some parts Being removed and some parts being disclosed n'oross section.

Figure 6 is a detail largely in cross section, the pian'e of which is indicated by the line 6-6 0T Figure 4. V

its preferred form, the sand wheel of my invention comprises a bucket mounted on a ro= gamble wheel to ffect movement of the bucket from a lower, upright position into and through an upper, inverted position. Encompassing the bucket and wheel. is a boot or tank for receiving a mixture of sand and water and for releasing Water from the structure Mounted on the framework which carries the wheel is a screen disposed beneath-the bucket in its upper, inverted position. The screen passes the liquid portion of the mixture discharged by the bucket thereupon for release frorn the apparatus and directs the solid portion of the mixture into a sand receiving' and discharging device effective to carry the separated sand and silt away from the sand wheel fordischarge at a remote point.

While the sand wheel of my invention can be embodied in various different forms and is subject to modification dependent upon the environrhent in which it is installed, it is successfully embodied and operated in the particular form shown in the drawings. In this installation the sand wheel is located on an alluvial or placer dredge including a floating hull 6 supported on a dredgepond and having a deck 1 and an enclosing house 8.

At suitable locationson the dredge, not shown, are value-saving mechanisms for processing a mixture of solid material and liquid. After a separating action the remaining sand and water are released into a discharge sluice 9 normally conducting the flnid miiiture to a convenient point of discharge over the stern of the dredge hull 6. The'discharge sluice 9 is duplicated symmetrically on the opposite side of the center line I I of the dredge. in fact. in the preferred installation, virtually ali'or the structure disclosed herein is arranged in duplicate and in symmetry on opposite sides or the dredge center line l I.

The dischargesluice 9' is provided with a pinrality of bottom perforations [2 effective to discharge any solid or heavy material traveling near or along the bottom of the sluice into a subiacent fiume l3. By the provision of this mechanism, all of the contained sand and silt in the fluid flowing in the discharge sluice 9 is diverted into the flume i3 and is conveyed by the attendant water toward the center of the dredge and into a boot M mounted on and supported by a framework is carried by the dredge deck I.

The framework It is fabricated of structural shapes and constitutes a skeleton enclosing and the flared lip 44 enters the water and engages the deposited fine material or sand within the bottom of the boot Id and transfers some of the sand and water into the bucket itself. As the bucket emerges from below the water level defined substantially by the lower margin of the weir aperture l'l, its water is spilled to a level initially defined by the position of the lip 44.

As the wheel continues to rotate (clockwise as seen in Figure 3) the contained material in the bucket shifts toward the center of the wheel with supporting the sheet metal boot M. The boot is a curved bottom, open-topped housing extending from a point below the discharge it of the flume I3 to a considerable elevation above the deck I of the dredge. It is open to the atmosphere at the top and is generally water-tight to serve as a retainer for the material discharged into it from Since the available volume of the boot i4 is considerable, the material discharged into it tends to separate by gravity so that silt and sand collect in the lower portion of the boot and the accompanying water stands over the sand and silt. In r.-

order that excessive water will not be retained, the side wall of the boot is provided with a water discharge aperture l l at a convenient height and of a contour to serve substantially as a weir. This opening affords egress for the separated water from within the boot. The water flows to a discharge channel Zll supported in part on the framework and leading the separated water, containing substantially no solids, to a convenient point of release from the dredge hull back into the dredge pond.

The result of the operation of the boot I 4 is to effectuate a mechanical separation by gravity of all consequential solids within the water stream flowing through the system. The largely clarified water discharged from the boot therefore is suitable for return to the dredge pond. There remain behind the separated solids accumulated in the lower or quiescent portion of the boot I4.

In order continually to remove such deposited solids, I provide within the boot l4 and on the framework it a revolving wheel 2| comprised of a central, conical frame 22 mounted on a tubular shaft 23 extending transversely through the side walls of the boot l4 and having a substantially water-tight seal therewith. The shaft 23 is journaled in bearings 24 mounted on the framework [6 so that upon the application of power to the shaft through a sprocket 26 secured thereto, the wheel is rotated. For driving the sprocket 23 a prime mover such as an electric motor 2'! is supported on a. pedestal 28 and is connected by a drive chain 29 so that the wheel is revolved slowly, for eXample. at the rate of two revolutions per minute.

The wheel framework 22 at its periphery carries a plurality or series of buckets 3i These buckets are all identical so that a description of one applies to all. The framework 22 includes a pair of bands 32 and 33 between them supporting the buckets by removable fastenings 34 so that the buckets can be removed for replacement or repair if necessary. Each of the buckets includes a pair of side walls 36 and 37 and an end wall 38 merging through a curved corner 39 with a bottom wall 4 I. An upturned inner flange 42 on the bottom wall defines a rectilinear edge 53 (Figure 5). The side walls 36 and 31 and the end wall 38 are augmented by a flaring lip 44.

The general positioning and orientation of the bucket 3! is such that as the wheel is revolved,

the level of the water moving toward the inner or'right-hand edge 43 of the bucket bottom 4!. During this time and due to the relatively slow rotation of the wheel, the material which is somewhat agitated when it is first entrained by the bucket again becomes quiescent and a gravital separation takes place with the sand in the bottom of the bucket and the water remaining in the upper portion thereof. The quantity contained is such that at about the time the bucket rises above its mid position, the water level has substantially attained the inner edge 53 of the bucket. As the bucket rises farther the water begins to spill overboard toward the interior of the wheel. A gravital separation having taken place, the sandy material remains behind covering the bottom of the bucket and being eifectively retained by the upwardly inclined lip l3. A large part of the bucket-contained water is thus discharged inwardly. It is intercepted by a plate 6.6 mounted interiorly of the wheel on the framework l6 and effective to prevent the water from falling into buckets in the lower portions of their travel. Rather the discharged water is diverted back into the lower portion of the boot for ultimate discharge through the weir opening ii. A large part of the water is thus discharged from the bucket and only a small amount remains mixed with the bucket sand.

To efiectuate further separation of the contained sand and water, the bucket as it nears the upper portion of its travel rides over a screen 5|. The screen is of sufficiently fine mesh so that the solid material cannot readily pass therethrough although the water readily passes. The screen is curved and ismounted on an extension of the metal boot I 4 in a position so that it is almost, but not quite, engaged by the edge 43 of the bucket. The substantial engagement begins at a position just prior to the time that the sand remaining in the bucket is gravitally discharged therefrom.

That is, just prior to the time that sand normally would fall from the bucket as the bucket approaches its upper inverted position, the bucket overrides the screen. Thus the screen intercepts the falling sand but permits the simultaneously- 7 discharged water to pass. As the bucket advances,

the edge 43 is effective to propel the discharged sand along and over the screen during which time it is turned and tumbled and any entrapped or entrained water is released for discharge. The

water separated from the sand and passing through the screen is diverted by a deflector plate 52 mounted on the metal boot 54. It directs the water to fall upon the deflector plate '1 and thus to return to the boot.

The angular extent of the screen 5! is such that it receives all or substantially all of the sand previously contained in the bucket.

over the screen is sufficient to permit the drainbucket propels the sand over the trailing edge The. time interval during which the bucket passes t of the screen into a hopper 53 located on the metal boot [4 at the zenith of the bucket travel so that in its uppermost, inverted position the bucket overlies the hopper 53. The hopper is of sufficient angular extent so that all of the boundary surfaces of the bucket are either vertical, or approximately vertical, before theyleave the hopper 53. In this fashion, the water is returned to the boot and the sand is discharged into the hopper. Continued rotation of the sand wheel advances the bucket from the boundary of the hopper 53* in a descending path until the bucket again enters the water in the boot to complete its cycle.

The sand discharges gravitally from the hopper through a chute 54 mounted on the framework I6 and extending from a position within the periphery of the wheel and beneath the hopper to a position (Figure 2) overlying the stacker conveyor 56 arranged on the median line of the dredge. The stacker conveyor is used to discharge rocks and coarse boulders from the dredge at a point considerably astern of the dredge hull, usually near the top of a tailing pile entirely outside of the boundary of the dredge pond. The separated sand discharged from the hopper 53 through the chute 54 onto the stacker conveyor 56 is mingled with the other material thereon and is likewise carried to a remote point astern of the dredge and beyond the boundary of the dredge pond. It is deposited on the tailings pile in a position where it cannot return to the dredge pond and remix. Thus the sand and water are entirely separated, the water is returned for recirculation, and the sand is removed beyond the boundary of the dredge pond.

I claim:

1. A sand wheel comprising: a frame, a wheel rotatably mounted on said frame on a generally horizontal axis, a bucket carried by said wheel radially spaced from said axis, said bucket being arranged on said wheel to be in material holding attitude in its lowermost position and to assume material dumping attitude in its uppermost position, a curved screen carried by said frame radially inwardly of said bucket and adjacent the uppermost position of said bucket, said screen being concentric to said axis and closely adjacent the path of travel of a portion of said bucket whereby material dumped from said bucket onto said screen will be engaged by said portion and moved over said screen.

2. A sand wheel comprising: a frame, a wheel rotatably mounted on said frame on a generally horizontal axis, a bucket carried by said wheel radially spaced from said axis, said bucket being arranged on said wheel to be in material holding attitude in its lowermost position and to assume material dumping attitude in its uppermost position, a curved screen carried by said frame radially inwardly of said bucket and adjacent the uppermost position of said bucket, said screen being concentric to said axis and closely adjacent the path of travel of a portion of said bucket, said screen extending from an upper terminus adjacent the uppermost position of said bucket to a lower terminus circumferentially spaced therefrom in the direction of approach of said bucket.

3. A sand wheel as defined in claim 2 and further including sand receiving means below the uppermost position of said bucket and positioned to receive sand moved over the upper terminus of said screen by said bucket.

4. A sand Wheel as defined in claim 1 wherein the said portion of said bucket comprises an axially extending radially innermost free edge of a side wall thereof.

EDWARD A. FOSTER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 366,026 Peters July 5, 1887 1,839,804 Perkins Jan. 5, 1932 2,303,367 Kendall et al Dec. 1, 1942 2,322,415 Buckbee June 22, 1943 FOREIGN PATENTS Number Country Date 215,566 Great Britain 1924 

